New! View global litigation for patent families

US6110333A - Composite membrane with highly crystalline porous support - Google Patents

Composite membrane with highly crystalline porous support Download PDF

Info

Publication number
US6110333A
US6110333A US09070040 US7004098A US6110333A US 6110333 A US6110333 A US 6110333A US 09070040 US09070040 US 09070040 US 7004098 A US7004098 A US 7004098A US 6110333 A US6110333 A US 6110333A
Authority
US
Grant status
Grant
Patent type
Prior art keywords
polymer
membrane
composite
exchange
ion
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Active
Application number
US09070040
Inventor
Jeffrey E. Spethmann
James Thomas Keating
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Donaldson Co Inc
Chemours Co FC LLC
Original Assignee
Donaldson Co Inc
E I du Pont de Nemours and Co
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Grant date

Links

Images

Classifications

    • HELECTRICITY
    • H01BASIC ELECTRIC ELEMENTS
    • H01MPROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL INTO ELECTRICAL ENERGY
    • H01M8/00Fuel cells; Manufacture thereof
    • H01M8/10Fuel cells with solid electrolytes
    • H01M8/1016Fuel cells with solid electrolytes characterised by the electrolyte material
    • H01M8/1018Polymeric electrolyte materials
    • H01M8/1067Polymeric electrolyte materials characterised by their physical properties, e.g. porosity, ionic conductivity or thickness
    • CCHEMISTRY; METALLURGY
    • C08ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
    • C08JWORKING-UP; GENERAL PROCESSES OF COMPOUNDING; AFTER-TREATMENT NOT COVERED BY SUBCLASSES C08B, C08C, C08F, C08G
    • C08J5/00Manufacture of articles or shaped materials containing macromolecular substances
    • C08J5/20Manufacture of shaped of ion-exchange resins Use of macromolecular compounds as anion B01J41/14 or cation B01J39/20 exchangers
    • C08J5/22Films, membranes, or diaphragms
    • C08J5/2206Films, membranes, or diaphragms based on organic and/or inorganic macromolecular compounds
    • C08J5/2218Synthetic macromolecular compounds
    • C08J5/2231Synthetic macromolecular compounds based on macromolecular compounds obtained by reactions involving unsaturated carbon-to-carbon bonds
    • C08J5/2243Synthetic macromolecular compounds based on macromolecular compounds obtained by reactions involving unsaturated carbon-to-carbon bonds obtained by introduction of active groups capable of ion-exchange into compounds of the type C08J5/2231
    • C08J5/225Synthetic macromolecular compounds based on macromolecular compounds obtained by reactions involving unsaturated carbon-to-carbon bonds obtained by introduction of active groups capable of ion-exchange into compounds of the type C08J5/2231 containing fluorine
    • CCHEMISTRY; METALLURGY
    • C08ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
    • C08JWORKING-UP; GENERAL PROCESSES OF COMPOUNDING; AFTER-TREATMENT NOT COVERED BY SUBCLASSES C08B, C08C, C08F, C08G
    • C08J5/00Manufacture of articles or shaped materials containing macromolecular substances
    • C08J5/20Manufacture of shaped of ion-exchange resins Use of macromolecular compounds as anion B01J41/14 or cation B01J39/20 exchangers
    • C08J5/22Films, membranes, or diaphragms
    • C08J5/2206Films, membranes, or diaphragms based on organic and/or inorganic macromolecular compounds
    • C08J5/2275Heterogeneous membranes
    • C08J5/2281Heterogeneous membranes fluorine containing heterogeneous membranes
    • CCHEMISTRY; METALLURGY
    • C25ELECTROLYTIC OR ELECTROPHORETIC PROCESSES; APPARATUS THEREFOR
    • C25BELECTROLYTIC OR ELECTROPHORETIC PROCESSES FOR THE PRODUCTION OF COMPOUNDS OR NON-METALS; APPARATUS THEREFOR
    • C25B13/00Diaphragms; Spacing elements
    • C25B13/04Diaphragms; Spacing elements characterised by the material
    • C25B13/08Diaphragms; Spacing elements characterised by the material based on organic materials
    • HELECTRICITY
    • H01BASIC ELECTRIC ELEMENTS
    • H01MPROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL INTO ELECTRICAL ENERGY
    • H01M8/00Fuel cells; Manufacture thereof
    • H01M8/02Details
    • H01M8/0289Means for holding the electrolyte
    • HELECTRICITY
    • H01BASIC ELECTRIC ELEMENTS
    • H01MPROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL INTO ELECTRICAL ENERGY
    • H01M8/00Fuel cells; Manufacture thereof
    • H01M8/10Fuel cells with solid electrolytes
    • H01M8/1016Fuel cells with solid electrolytes characterised by the electrolyte material
    • H01M8/1018Polymeric electrolyte materials
    • H01M8/102Polymeric electrolyte materials characterised by the chemical structure of the main chain of the ion-conducting polymer
    • H01M8/1023Polymeric electrolyte materials characterised by the chemical structure of the main chain of the ion-conducting polymer having only carbon, e.g. polyarylenes, polystyrenes or polybutadiene-styrenes
    • HELECTRICITY
    • H01BASIC ELECTRIC ELEMENTS
    • H01MPROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL INTO ELECTRICAL ENERGY
    • H01M8/00Fuel cells; Manufacture thereof
    • H01M8/10Fuel cells with solid electrolytes
    • H01M8/1016Fuel cells with solid electrolytes characterised by the electrolyte material
    • H01M8/1018Polymeric electrolyte materials
    • H01M8/102Polymeric electrolyte materials characterised by the chemical structure of the main chain of the ion-conducting polymer
    • H01M8/1025Polymeric electrolyte materials characterised by the chemical structure of the main chain of the ion-conducting polymer having only carbon and oxygen, e.g. polyethers, sulfonated polyetheretherketones [S-PEEK], sulfonated polysaccharides, sulfonated celluloses or sulfonated polyesters
    • HELECTRICITY
    • H01BASIC ELECTRIC ELEMENTS
    • H01MPROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL INTO ELECTRICAL ENERGY
    • H01M8/00Fuel cells; Manufacture thereof
    • H01M8/10Fuel cells with solid electrolytes
    • H01M8/1016Fuel cells with solid electrolytes characterised by the electrolyte material
    • H01M8/1018Polymeric electrolyte materials
    • H01M8/102Polymeric electrolyte materials characterised by the chemical structure of the main chain of the ion-conducting polymer
    • H01M8/1032Polymeric electrolyte materials characterised by the chemical structure of the main chain of the ion-conducting polymer having sulfur, e.g. sulfonated-polyethersulfones [S-PES]
    • HELECTRICITY
    • H01BASIC ELECTRIC ELEMENTS
    • H01MPROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL INTO ELECTRICAL ENERGY
    • H01M8/00Fuel cells; Manufacture thereof
    • H01M8/10Fuel cells with solid electrolytes
    • H01M8/1016Fuel cells with solid electrolytes characterised by the electrolyte material
    • H01M8/1018Polymeric electrolyte materials
    • H01M8/1039Polymeric electrolyte materials halogenated, e.g. sulfonated polyvinylidene fluorides
    • HELECTRICITY
    • H01BASIC ELECTRIC ELEMENTS
    • H01MPROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL INTO ELECTRICAL ENERGY
    • H01M8/00Fuel cells; Manufacture thereof
    • H01M8/10Fuel cells with solid electrolytes
    • H01M8/1016Fuel cells with solid electrolytes characterised by the electrolyte material
    • H01M8/1018Polymeric electrolyte materials
    • H01M8/1041Polymer electrolyte composites, mixtures or blends
    • H01M8/1053Polymer electrolyte composites, mixtures or blends consisting of layers of polymers with at least one layer being ionically conductive
    • HELECTRICITY
    • H01BASIC ELECTRIC ELEMENTS
    • H01MPROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL INTO ELECTRICAL ENERGY
    • H01M8/00Fuel cells; Manufacture thereof
    • H01M8/10Fuel cells with solid electrolytes
    • H01M8/1016Fuel cells with solid electrolytes characterised by the electrolyte material
    • H01M8/1018Polymeric electrolyte materials
    • H01M8/1058Polymeric electrolyte materials characterised by a porous support having no ion-conducting properties
    • H01M8/106Polymeric electrolyte materials characterised by a porous support having no ion-conducting properties characterised by the chemical composition of the porous support
    • HELECTRICITY
    • H01BASIC ELECTRIC ELEMENTS
    • H01MPROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL INTO ELECTRICAL ENERGY
    • H01M8/00Fuel cells; Manufacture thereof
    • H01M8/10Fuel cells with solid electrolytes
    • H01M8/1016Fuel cells with solid electrolytes characterised by the electrolyte material
    • H01M8/1018Polymeric electrolyte materials
    • H01M8/1058Polymeric electrolyte materials characterised by a porous support having no ion-conducting properties
    • H01M8/1062Polymeric electrolyte materials characterised by a porous support having no ion-conducting properties characterised by the physical properties of the porous support, e.g. its porosity or thickness
    • CCHEMISTRY; METALLURGY
    • C08ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
    • C08JWORKING-UP; GENERAL PROCESSES OF COMPOUNDING; AFTER-TREATMENT NOT COVERED BY SUBCLASSES C08B, C08C, C08F, C08G
    • C08J2327/00Characterised by the use of homopolymers or copolymers of compounds having one or more unsaturated aliphatic radicals, each having only one carbon-to-carbon double bond, and at least one being terminated by a halogen; Derivatives of such polymers
    • C08J2327/02Characterised by the use of homopolymers or copolymers of compounds having one or more unsaturated aliphatic radicals, each having only one carbon-to-carbon double bond, and at least one being terminated by a halogen; Derivatives of such polymers not modified by chemical after-treatment
    • C08J2327/12Characterised by the use of homopolymers or copolymers of compounds having one or more unsaturated aliphatic radicals, each having only one carbon-to-carbon double bond, and at least one being terminated by a halogen; Derivatives of such polymers not modified by chemical after-treatment containing fluorine atoms
    • C08J2327/18Homopolymers or copolymers of tetrafluoroethylene
    • HELECTRICITY
    • H01BASIC ELECTRIC ELEMENTS
    • H01MPROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL INTO ELECTRICAL ENERGY
    • H01M2300/00Electrolytes
    • H01M2300/0017Non-aqueous electrolytes
    • H01M2300/0065Solid electrolytes
    • H01M2300/0082Organic polymers
    • HELECTRICITY
    • H01BASIC ELECTRIC ELEMENTS
    • H01MPROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL INTO ELECTRICAL ENERGY
    • H01M2300/00Electrolytes
    • H01M2300/0088Composites
    • H01M2300/0094Composites in the form of layered products, e.g. coatings

Abstract

A composite membrane including an ion exchange polymer and a support of expanded polytetrafluoroethylene polymer having a porous microstructure of polymeric fibrils, said expanded polytetrafluoroethylene polymer being at least about 85% crystalline.

Description

RELATED APPLICATIONS

This application claims the benefit of U.S. Provisional Application No. 60/046,814, filed May 2, 1997.

FIELD OF INVENTION

This invention relates to composite membranes and more particularly to composite ion exchange membranes of highly fluorinated ion exchange polymers with porous support films of a highly fluorinated nonionic polymer.

BACKGROUND OF THE INVENTION

Ion exchange polymer membranes have found utility in a number of electrochemical and other processes. One use has been as membranes for solid polymer electrolyte cells. Solid polymer electrolyte cells typically employ a membrane of an ion exchange polymer which serves as a physical separator between the anode and cathode while also serving as an electrolyte. These cells can be operated as electrolytic cells for the production of chemical products or they may be operated as fuel cells for the production of electrical energy. Ion exchange polymer membranes are also used for facilitated transport, diffusion dialysis, electrodialysis, pervaporation and vapor permeation separations.

Polymer ion exchange membranes must have sufficient strength to be useful in these various applications. Membranes of highly fluorinated polymers such as perfluorinated sulfonic acid polymer membranes are particularly well-suited for use in such cells due to excellent chemical resistance, long life, and high conductivity. However, for some applications, the tensile strength of such membranes is not as high as desired. If increased physical strength is achieved by making the membrane thicker, a decrease in ionic conductance may result. Reinforcement are sometimes incorporated into the membranes to increase strength. For example, in membranes used in the chloralkali process, i.e., the production of caustic and chlorine by electrolytic conversion of an aqueous solution of an alkali metal chloride, woven reinforcements are incorporated into the membranes. For other applications such as in fuel cells, increased tensile strength is typically not needed in use but may be desirable for ease of handling or for certain manufacturing operations involving the membranes.

Reinforcement of polymer ion exchange membranes to confer improved physical properties has been disclosed in a number of prior art references. A number of references disclose combining porous expanded polytetrafluoroethylene (EPTFE) with highly fluorinated ion exchange polymer. For example, in U.S. Pat. No. 3,692,569 (Grot), surface active fluorocarbon objects are described as a composite structure of an inert fluorocarbon polymer core with a chemically modified fluorocarbon copolymer surface which confers chemical activity to the structure. Exemplified is a fluorocarbon core which is a porous support film of polytetrafluoroethylene and which is coated with a fluorocarbon copolymer with pendant chemically active sulfonyl groups. The coating copolymer either forms a coating in the pores or fills the pores depending on the desired use of the structure.

U.S. Pat. No. 4,902,308 (Mallouk et al.) describes a sheet of porous expanded polytetrafluoroethylene coated with a reactive metal salt of perfluorinated ion exchange polymer for use in scavenging unwanted gas components.

U.S. Pat. No. 5,082,472 (Mallouk et al.) discloses a dimensionally stable composite membrane for use in facilitated transport unit operations. The composite is described as a porous expanded polytetrafluoroethylene in laminar contact with a continuous perfluorinated ion exchange resin layer, the ion exchange layer being swollen with a hydrophilic liquid.

U.S. Pat. No. 4,954,388 (Mallouk et al.) discloses an abrasion-resistant, tear resistant, multilayer composite membrane for use in electrolysis. The composite membrane is described as having a perfluorinated ion exchange layer attached to a reinforcing fabric by means of an interlayer of porous expanded polytetrafluoroethylene.

U.S. Pat. No. 5,547,551 (Bahar et al.) discloses an ultra-thin composite membrane of porous expanded polytetrafluoroethylene impregnated with ion exchange polymer. The base material is defined by a thickness of less than 1 mil (0.025 mm) with the ion exchange resin impregnating the membrane such that the membrane is essentially air impermeable.

The process for producing porous expanded polytetrafluoroethylene support films used in reinforcing ion exchange membrane is described in U.S. Pat. Nos. 3,953,566 and 3,962,153 (both to Gore). The references teach a method of rapidly stretching a paste-formed film of highly crystalline PTFE and then heat treating (or sintering) it to increase the amorphous content of the PTFE to typically greater than 10%. The resultant structure is expanded, amorphous-locked polytetrafluoroethylene film having a porous microstructure of polymeric fibrils which is easily bonded to other materials.

Although the prior art has shown ways of strengthening ion exchange membranes by reinforcement porous expanded PTFE supports, tear strength has not been as high as is desirable. A composite membrane is needed for application in electrochemical processes which possesses greater tear strength without sacrificing performance.

SUMMARY OF THE INVENTION

The invention provides for a composite membrane comprising an ion exchange polymer and a support of expanded polytetrafluoroethylene polymer having a porous microstructure of polymeric fibrils, the expanded polytetrafluoroethylene polymer being at least about 85% crystalline.

In a preferred form of the invention, the ion exchange polymer is highly fluorinated and preferably the ion exchange groups are sulfonate groups.

In a preferred form of the invention the composite membrane has a wet tear strength as determined by ASTM D1922 of at least about 10 kN/m, preferably at least about 100 kN/m and more preferably at least about 200 kN/m.

In a preferred form of the invention the ion exchange polymer of the composite membrane has an ion exchange ratio of about 8 to about 23, preferably 9 to about 14, and more preferably about 10 to 13.

If desired, the composite membrane has fabric attached to the porous support and has particular use in chloralkali processes.

If desired, the porous support is fully embedded in the ion exchange polymer and the nonionic polymer of porous support comprises less than about 15% by weight of the membrane and the resulting composite membrane has particular use in fuel cell applications.

In accordance with a preferred form of the present invention, a composite membrane is provided which includes a highly fluorinated ion exchange polymer and a porous support consisting essentially of expanded highly fluorinated nonionic polymer having a porous microstructure of polymeric fibrils. The membrane has a wet tear strength as determined by ASTM D1922 of at least about 10 kN/m, preferably at least about 100 kN/m, and most preferably at least about 200 kN/m.

The composite membrane of the invention is advantageously employed in an electrochemical cell comprising an anode and a cathode partitioned by the composite membrane. The electrochemical cell preferably is operated as a fuel cell or operated to produce an alkali metal hydroxide and chlorine by the electrolytic conversion of an alkali metal chloride.

DETAILED DESCRIPTION

Ion Exchange Polymers

Polymers for use in accordance with this invention may be any number of ion exchange polymers including polymers with cation exchange groups that are preferably selected from the group consisting of sulfonate, carboxylate, phosphonate, imide, sulfonimide and sulfonamide groups. Various known cation exchange polymers can be used including polymers and copolymers of trifluoroethylene, tetrafluoroethylene, styrene-divinyl benzene, α,β,β-trifluorstyrene, etc., in which cation exchange groups have been introduced.

Polymers for use in accordance with the present invention are preferably highly fluorinated ion-exchange polymers having sulfonate ion exchange groups. "Highly fluorinated" means that at least 90% of the total number of univalent atoms in the polymer are fluorine atoms. Most preferably, the polymer is perfluorinated. The term "sulfonate ion exchange groups" is intended to refer to either to sulfonic acid groups or salts of sulfonic acid groups, preferably alkali metal or ammonium salts. Most preferably, the ion exchange groups are represented by the formula --SO3 X wherein X is H, Li, Na, K or N(R1)(R2)(R3)(R4) and R1, R2, R3, and R4 are the same or different and are H, CH3 or C2 H5. For applications where the polymer is to be used for proton exchange, the sulfonic acid form of the polymer is preferred, i.e., where X is H in the formula above. For use in the chloralkali process, the sodium salt form of the polymer preferred, i.e., where X is Na in the formula above.

Preferably, the polymer comprises a polymer backbone with recurring side chains attached to the backbone with the side chains carrying the cation exchange groups. Possible polymers include homopolymers or copolymers of two or more monomers. Copolymers are typically formed from one monomer which is a nonfunctional monomer and which provides carbon atoms for the polymer backbone. A second monomer provides both carbon atoms for the polymer backbone and also contributes the side chain carrying the cation exchange group or its precursor, e.g., a sulfonyl halide group such a sulfonyl fluoride (--SO2 F), which can be subsequently hydrolyzed to a sulfonate ion exchange group. For example, copolymers of a first fluorinated vinyl monomer together with a second fluorinated vinyl monomer having a sulfonyl fluoride group (--SO2 F) can be used. Possible first monomers include tetrafluoroethylene (TFE), hexafluoropropylene, vinyl fluoride, vinylidine fluoride, trifluorethylene, chlorotrifluoroethylene, perfluoro (alkyl vinyl ether), and mixtures thereof. Possible second monomers include a variety of fluorinated vinyl ethers with sulfonate ion exchange groups or precursor groups which can provide the desired side chain in the polymer. The first monomer may also have a side chain which does not interfere with the ion exchange function of the sulfonate ion exchange group. Additional monomers can also be incorporated into these polymers if desired.

A class of preferred polymers for use in the present invention includes a highly fluorinated, most preferably perfluorinated, carbon backbone and the side chain is represented by the formula --(O--CF2 CFR.sub.ƒ)a --O--CF2 CFR'.sub.ƒ SO3 X, wherein R.sub.ƒ and R'.sub.ƒ are independently selected from F, Cl or a perfluorinated alkyl group having 1 to 10 carbon atoms, a=0, 1 or 2, and X is H, Li, Na, K or N(R1)(R2)(R3)(R4) and R1, R2, R3, and R4 are the same or different and are H, CH3 or C2 H5. The preferred polymers include, for example, polymers disclosed in U.S. Pat. No. 3,282,875 and in U.S. Pat. Nos. 4,358,545 and 4,940,525. One preferred polymer comprises a perfluorocarbon backbone and the side chain is represented by the formula --O--CF2 CF(CF3)--O--CF2 CF2 SO3 X, wherein X is as defined above. Polymers of this type are disclosed in U.S. Pat. No. 3,282,875 and can be made by copolymerization of tetrafluoroethylene (TFE) and the perfluorinated vinyl ether CF2 ═CF--O--CF2 CF(CF3)--O--CF2 CF2 SO2 F, perfluoro(3,6-dioxa-4-methyl-7-octenesulfonyl fluoride) (PDMOF), followed by conversion to sulfonate groups by hydrolysis of the sulfonyl halide groups and ion exchanging if needed to convert to the desired form. One preferred polymer of the type disclosed in U.S. Pat. Nos. 4,358,545 and 4,940,525 has the side chain --O--CF2 CF2 SO3 X, wherein X is as defined above. This polymer can be made by copolymerization of tetrafluoroethylene (TFE) and the perfluorinated vinyl ether CF2 ═CF--O--CF2 CF2 SO2 F, perfluoro(3-oxa-4-pentenesulfonyl fluoride) (POPF), followed by hydrolysis and ion exchange if needed.

In preferred forms of the present invention, highly fluorinated carboxylate polymer, i.e., having carboxylate ion exchange groups in the resulting composite membrane, is also employed as will be discussed in more detail hereinafter. The term "carboxylate ion exchange groups" is intended to refer to either carboxylic acid groups or salts of carboxylic acid groups, preferably alkali metal or ammonium salts. Most preferably, the ion exchange groups are represented by the formula --CO2 X wherein X is H, Li, Na, K or N(R1)(R2)(R3)(R4) and R1, R2, R3, and R4 are the same or different and are H, CH3 or C2 H5. For use in the chloralkali process, the sodium salt form of the polymer is preferred, i.e., where X is Na in the formula above. Preferably, the polymer comprises a polymer backbone with recurring side chains attached to the backbone with the side chains carrying the carboxylate ion exchange groups. Polymers of this type are disclosed in U.S. Pat. No. 4,552,631 and most preferably have the side chain --O--CF2 CF(CF3)--O--CF2 CF2 CO2 X. This polymer can be made by copolymerization of tetrafluoroethylene (TFE) and the perfluorinated vinyl ether CF2 ═CF--O--CF2 CF(CF3)--O--CF2 CF2 CO2 CH3, methyl ester of perfluoro(4,7-dioxa-5-methyl-8-nonenecarboxylic acid) (PDMNM), followed by conversion to carboxylate groups by hydrolysis of the methyl carboxylate groups and ion exchanging if needed to convert to the desired form. While other esters can be used for film or bifilm fabrication, the methyl ester is the preferred since it is sufficiently stable during normal extrusion conditions.

In this application, "ion exchange ratio" or "IXR" is defined as number of carbon atoms in the polymer backbone in relation to the cation exchange groups. A wide range of IXR values for the polymer are possible. Typically, however, the IXR range used for layers of the laminated membrane is usually about 7 to about 33. For perfluorinated polymers of the type described above, the cation exchange capacity of a polymer is often expressed in terms of equivalent weight (EW). For the purposes of this application, equivalent weight (EW) is defined to be the weight of the polymer in acid form required to neutralize one equivalent of NaOH. In the case of a sulfonate polymer where the polymer comprises a perfluorocarbon backbone and the side chain is --O--CF2 --CF(CF3)--O--CF2 --CF2 --SO3 H (or a salt thereof), the equivalent weight range which corresponds to an IXR of about 7 to about 33 is about 700 EW to about 2000 EW. IXR for this polymer can be related to equivalent weight using the following formula: 50 IXR+344=EW. While generally the same IXR range is used for sulfonate polymers disclosed in U.S. Pat. Nos. 4,358,545 and 4,940,525, the equivalent weight is somewhat lower because of the lower molecular weight of the monomer unit containing a cation exchange group. For the IXR range of about 7 to about 33, the corresponding equivalent weight range is about 500 EW to about 1800 EW. IXR for this polymer can be related to equivalent weight using the following formula: 50 IXR+178=EW. For carboxylate polymers having the side chain --O--CF2 CF(CF3)--O--CF2 CF2 CO2 X, a useful IXR range is about 12 to about 21 which corresponds to about 900 EW to about 1350 EW. IXR for this polymer can be related to equivalent weight using the following formula: 50 IXR+308=EW.

IXR is used in this application to describe either hydrolyzed polymer which contains ion exchange groups or unhydrolyzed polymer which contains precursor groups which will subsequently be converted to the ion exchange groups during the manufacture of the membranes.

The highly fluorinated sulfonate polymer used in the process of the invention preferably has ion exchange ratio of about 8 to about 23, preferably about 9 to about 14 and most preferably about 10 to about 13.

Porous Support

The support used in the present invention is expanded polytetrafluoroethylene polymer (EPTFE) in one of two forms: (1) a porous microstructure which has nodes interconnected by polymeric fibrils (2) a porous microstructure comprised substantially of polymeric fibrils with no nodes present. Both forms of the EPTFE support are characterized by a high crystalline content of at least 85%, preferably at least 90%, more preferably at least 95% and most preferably at least 98%. Crystalline content can be measured by the method described by Moynihan, R. E., "IR Studies on Polytetrafluoroethylene", J. Am. Chem. Soc. 81, 1045-1050 (1959).

The preparation of the two forms of EPTFE support are described in U.S. Pat. No. 3,593,566 and U.S. Pat. No. 5,547,551 with the exception that in the present invention no heat treatment (or sintering step) is performed after extrusion and biaxially stretching. These prior art references both teach that extruded PTFE tape is heated to above its melting point (approximately 342° C.) while constrained after sequential longitudinal and transverse expansion.

Heat treating (or sintering) is performed to increase the amorphous content of the EPTFE to typically greater than 10%. According to the prior art teaching the amorphous regions within the crystalline structure inhibit slippage along the crystalline axis of the crystallite and lock the fibrils so that they resist slippage under stress. The heat treatment is considered as an amorphous locking process which increases the amorphous content of the polymer.

In contrast, the present invention uses a microporous support structure with a high crystalline content can be achieved by not sintering the EPTFE and thereby avoiding the introducing of amorphous regions into the structure. The microporous support of the present invention can be distinguished from the microporous structures described in the prior art by differential scanning calorimetry. The technique is described in Thermal Characterization of Polymeric Materials, E. A. Turi, ed., Academic Press, New York 1981, ch. 1,3. As is evident in Table 1, two commercial products (Sample I and Sample II) of EPTFE, when evaluated by differential scanning calorimetry, exhibit a reduction in melting point and a reduced crystallinity (magnitude of the endotherm) of the polymer when compared to unsintered Sample III. The 346° C. melting point and 81 J/g endotherm of unsintered EPTFE are characteristic of PTFE which has never been heated above its melting point. Sample II has two peaks and an intermediate crystallinity, indicating that it has been sintered to a lesser extent than Sample I.

              TABLE 1______________________________________Expanded     Endotherm   EndothermPTFE         peak temp.  area (J/g)______________________________________SAMPLE ISintered     336° C.                    54SAMPLE IISintered     332° C./345° C.                    69SAMPLE IIIUnsintered   346° C.                    81______________________________________

The heat treatment or sintering step described in U.S. Pat. No. 3,593,566 and U.S. Pat. No. 5,547,551 is credited with increasing the tensile strength of the EPTFE sheet. Surprisingly, however, applicants have discovered that the composite membrane in accordance with the present invention with support of expanded polytetrafluoroethylene which has not been sintered, exhibits greatly improved wet tear strength.

The composite membrane of the present invention preferably has a wet tear strength as determined by ASTM D1922 of at least about 10 kN/m, preferably of at least about 100 kN/m, most preferably of at least about 200 kN/m. Of particular interest is a composite membrane having a highly fluorinated ion exchange polymer and a porous support consisting essentially of expanded highly fluorinated nonionic polymer having a porous microstructure of polymeric fibrils. This membrane has a wet tear strength as determined by ASTM D1922 of at least about 10 kN/m preferably of at least about 100 kN/m, most preferably of at least 200 kN/m. "A porous support consisting essentially of expanded highly fluorinated nonionic polymer having a porous microstructure of polymeric fibrils" in the present application means that there is no other reinforcement associated with porous support such as fabrics, scrim, etc. and the tear strength is provided essentially only by the expanded highly fluorinated nonionic polymer having a porous microstructure of polymeric fibrils in combination with the ion exchange polymer in the membrane.

Composite membranes of the present invention are more robust in handling and may be converted or used in a number of manufacturing processes more easily.

Membrane Manufacture

The composite membrane of the present invention is formed by combining ion exchange polymer and EPTFE. This can be accomplished in a number of different ways. The composite can be made by impregnating the porous support with cation exchange polymer so that the coating is on the outside surfaces as well as being distributed through the internal pores of the support. The polymer may partially or completely fill the pores of the expanded support structure. This may be accomplished by impregnating the porous support with a solution or dispersion of the cation exchange polymer or cation exchange polymer precursor using a solvent or dispersion medium which is not harmful to the polymer of the support under the impregnation conditions. For example, for impregnating perfluorinated sulfonic acid polymer into a microporous EPTFE support, a 1-10 weight percent dispersion of the polymer in a polar solvent such as an alcohol/water mixture can be used. Impregnation can be performed using a variety of techniques including dipping, soaking, brushing, painting and spraying as well as using conventional coating methods such as forward roll coating, reverse roll coating, gravure coating, doctor coating, kiss coating, etc. After impregnation, the support with the solution/dispersion is dried to form the membrane. The impregnation and drying steps are repeated as needed to apply the desired amount of polymer.

In addition to impregnation, thin films of the ion exchange polymer can be laminated to one or both sides of the impregnated porous support. A number of techniques may be used including hot roll lamination, melt deposition of the polymer and numerous other methods taking care not to damage the integrity of the EPTFE support. The process used for making this laminate preferably causes sufficient adhesion between the porous support film that delamination does not occur during subsequent handling or processing including hydrolysis.

The composite membrane of present invention has a thickness of 20 μm to about 400 μm, preferably 30 μm to about 60 μm. Additionally, the composite membrane of the present invention may be reinforced with a woven or a nonwoven material or fabric bonded to one side of the composite membrane. Such structures have particular application in chloralkali processing. Suitable woven materials include scrims of woven fibers of EPTFE, webs of extruded or oriented fluoropolymer or fluoropolymer netting, and woven materials of fluoropolymer fiber. Suitable nonwoven materials include spun-bonded fluoropolymer.

For applications such as chloralkali membranes where it is desired for the composite membrane to have a layer of highly fluorinated carboxylate polymer, a bifilm of highly fluorinated sulfonyl halide polymer and highly fluorinated carboxylate polymer precursor can be prepared for subsequent lamination. Suitable highly fluorinated carboxylate polymers are disclosed in U.S. Pat. No. 4,552,631 (Bissot et al.). Preferably, the highly fluorinated carboxylate polymer precursor is highly fluorinated methyl carboxylate polymer. Most preferably, the carboxylate polymer is perfluorinated. The bifilm can be prepared by extrusion of each layer followed by lamination or by coextrusion of the component polymers to make a two layer film. The bilayer film is then laminated directly to the EPTFE or laminated to a composite membrane of the present invention with the sulfonyl fluoride side of the bilayer film contacting the composite membrane so that it is adjacent the highly fluorinated ion exchange polymer (e.g., sulfonyl fluoride). The bifilm may also be coextruded and directly deposited onto the EPTFE. The bifilm/composite membrane structure is preferably modified on the outer surface so as to have enhanced gas release properties as described in the teachings of U.S. Pat. No. 4,552,631 (Bissot et al.)

Of particular interest for use in fuel cells is a composite membrane of this invention in which is the EPTFE support structure is fully embedded in the ion exchange polymer so as to provide flat surfaces desired for contact with the electrodes. In such a composite membrane the nonionic polymer of porous support comprises less than about 15% by weight of the composite membrane. The fully embedded composite membrane may be formed by laminating, impregnating and/or coating the EPTFE. The fully embedded composite membrane of this invention preferably has a layer of unreinforced ion exchange polymer with a thickness of at least about 2 μm provided at each surface of the membrane and most preferably has at least about 5 μm provided at each surface of the membrane.

One preferred process for making the membranes using both film lamination and impregnation is described in the following paragraphs.

The process includes fabricating a layered membrane precursor including a porous support of expanded highly fluorinated nonionic polymer adhered to a layer of highly fluorinated sulfonyl halide polymer. This can be accomplished by a variety of methods including lamination, melt deposition and other methods.

A film of sulfonyl halide polymer such as sulfonyl fluoride polymer for lamination to the support is suitably made by extrusion at a temperature in the range of about 200° C. to about 300° C. Preferable film thicknesses are about 10 μm to about 250 μm. For applications such as chloralkali membranes where it is desired for the composite membrane to layer of highly fluorinated carboxylate polymer, a bifilm of a layer of highly fluorinated sulfonyl halide polymer and a layer highly fluorinated carboxylate polymer precursor can be coextruded for subsequent lamination or coextruded directly onto the porous support.

In a preferred form of the invention, the layered membrane precursor is fabricated under conditions so that sufficient flow of the highly fluorinated sulfonyl halide polymer occurs to form a consolidated layered membrane precursor which does not delaminate during subsequent hydrolysis. Preferably, this is accomplished by laminating the film of highly fluorinated sulfonyl halide polymer to the microporous support at a temperature of at least about 280° C., most preferably at a temperature of at least about 300° C. These temperatures provide thermoplastic flow of the polymer sufficient to form the preferred consolidated layered membrane precursor.

The lamination process is preferably performed under pressure. Pressures in the range of about 0.5 to about 1 atmosphere (about 50 kPa to about 100 kPa) have been found to be suitable. Such pressures are advantageously applied by subjecting the microporous support to a vacuum while keeping the sulfonyl halide polymer film side at atmospheric pressure. Depending on the temperature, contact times can be as little as 5 seconds but generally are less than 90 seconds to avoid overheating and degradation of the polymer.

In the process of the invention, the layered membrane precursor, with or without the additional carboxylate polymer precursor layer, is suitably hydrolyzed using methods known in the art. For example, the membrane may be hydrolyzed to convert it to the sodium sulfonate form by immersing it in 25% by weight NaOH for about 16 hours at a temperature of about 90° C. followed by rinsing the film twice in deionized 90° C. water using about 30 to about 60 minutes per rinse. Another possible method employs an aqueous solution of 6-20% of an alkali metal hydroxide and 5-40% polar organic solvent such as dimethyl sulfoxide with a contact time of at least 5 minutes at 50°-100° C. followed by rinsing for 10 minutes. The carboxylate polymer precursor, such as methyl carboxylate polymer, if present, is converted to carboxylate polymer at the same time. After hydrolyzing, the membrane precursor can be converted if desired to another ionic form by contacting the membrane in a bath containing a 1-5% salt solution containing the desired cation or, to the acid form, by contacting with a 2-20% aqueous acid solution and rinsing. For fuel cell use, the membrane is usually in the sulfonic acid form. For chloralkali membranes, the membrane precursor is typically used in the sodium form.

Impregnation of the microporous support of the hydrolyzed precursor laminate is performed with liquid composition of highly fluorinated sulfonic acid polymer or precursor thereof in a polar liquid medium. By "polar liquid medium" is meant liquids which can be transported by a highly fluorinated sulfonate membrane. Suitable compositions of sulfonic acid polymer in polar media are disclosed in U.S. Pat. Nos. 4,433,082 and 4,453,991 in which polymer particles are dispersed mixtures of water and alcohols. Preferably, the polar medium contains a high content of an alcohol which facilitates wetting of the microporous support and which is volatile to facilitate the removal of the liquid medium from the membrane. Most preferably, the liquid compositions contain at least about 90% of an alcohol selected from the group consisting of alcohols with 1 to 4 carbon atoms. A suitable concentration of polymer in the liquid medium is about 2 to about 10% by weight. Compositions with high alcohol contents can be made by concentrating the compositions as disclosed in U.S. Pat. Nos. 4,433,082 and 4,453,991 by evaporation and subsequent dilution with the desired alcohol.

Impregnation is performed so that the pores of the microporous support are at least partially filled, but preferably are completely filled with polymer. Most preferably, impregnation is performed so that the microporous support is embedded in the highly fluorinated sulfonate polymer, i.e., an unreinforced layer of the sulfonate polymer is present on both surfaces of the microporous support.

Impregnation can be carried out using a variety of methods such as dipping, soaking, brushing, painting and spraying as well as using conventional coating methods such as forward roll coating, reverse roll coating, gravure coating, doctor coating, kiss coating etc. In order to impregnate to the desired degree, repeated steps of impregnation and/or removal of the liquid medium (as discussed in more detail hereinafter) may be necessary.

Removal of the liquid medium can be accomplished by heating and the liquid medium can be recycled if desired. Preferably, during the impregnating of the microporous support, the side of the membrane with the highly fluorinated sulfonate polymer layer is contacted with a dry gas to cause at least partial removal of the polar liquid by passage through the layer of highly fluorinated sulfonate polymer. "Dry gas" as used herein is meant a gas which has a sufficiently low content of vapor of the polar liquid medium to cause removal of the medium from the membrane. The sulfonate polymer layer on the membrane thus serves to draw liquid composition into the microporous support and assists with the impregnation process. In addition, the ability to remove the liquid medium by transport through the membrane enables the process to be performed very quickly which is very helpful for continuous processes. One or a series of solvent removal stages can be employed depending on the dispersion application method and other process requirements.

It is preferable to coalesce the polymer impregnating the porous support. The polymer impregnating the porous support can be coalesced by heating to a temperature which renders the polymer insoluble. While the coalescence temperature varies with the IXR of the polymer, typically the membrane should be heated to above about 120° C. A preferred temperature range is about 120 to about 150° C. for compolymers of TFE and PDMOF in the normal IXR ranges employed. For other polymers and for higher IXR values, higher temperatures may be desirable. The time needed coalesce varies with the temperature employed a suitable range has been found to be about one minute to about one hour. Coalescence is conveniently carried out together with or immediately following the removal of the liquid medium if desired.

While the process of the invention can be performed to make discrete pieces of composite membrane, the invention is advantageously carried out by performing some or a number of the steps of the process in a continuous fashion using roll stock. In one preferred form of the process, steps needed to fabricate the layered membrane precursor are combined in to one stage using roll stock of the microporous support and laminating to sulfonyl halide or bifilm film roll stock or by extrusion deposition of the sulfonyl halide polymer, optionally coextruded with the carboxylate polymer precursor. The layer membrane precursor can be wound up using a roll wind-up if desired. Hydrolysis (and acid exchange if used) can be performed in a separate stage by feeding the roll of layered membrane precursor into a hydrolysis bath following by drying and winding up. Impregnation can be performed after hydrolysis in a continuous fashion if desired. Generally, however, it is more advantageous to perform the steps of impregnation, removal of the liquid medium and coalescence of the polymer together as a stage of the process.

The invention is illustrated in the following examples which are not intended to be limiting.

EXAMPLES Example A

Composite Membrane with Sintered EPTFE

A sintered expanded PTFE structure (EPTFE), disclosed in U.S. Pat. Nos. 3,962,153 (Gore) and 3,953,566 (Gore), is used as a reinforcing layer in a composite membrane. The EPTFE has a nominal thickness of 0.004 inch (100 μm ) and an apparent density of about 0.38 g/cc.

A 1 mil (0.001 inch, 25 μm) thick perfluorosulfonyl fluoride polymer film of 1080 equivalent weight is prepared by melt extrusion of the perfluorosulfonyl fluoride form of the polymer onto a rotating drum, the film then being conveyed and cowound on a steel core with polyethylene film as an interleaf to prevent self adhesion of the cast film. Extrusion temperature is approximately 275° C.

The 1 mil (0.001 inch, 25 μm) 1080 EW sulfonyl fluoride film is then laminated to the EPTFE structure by vacuum lamination using a vacuum roll at 250° C. aided by a horseshoe heater at 325° C. with a vacuum of 70 kPa to form a composite membrane.

A bifilm of 1 mil (0.001 inch, 25 μm) 1050 EW highly fluorinated carboxylate film adhered to 4 mil (0.004 inch, 102 μm) 1080 EW sulfonyl fluoride film is prepared by extrusion and lamination of the component films, or by coextrusion of the component polymers to make a two layer film. The bifilm is then laminated to the composite membrane prepared above with the sulfonyl fluoride side of the bifilm contacting the sulfonyl fluoride side of the composite using conditions similar to those used to laminate the 1 mil (0.001 inch, 25 μm) sulfonyl fluoride film to the EPTFE structure.

Squares, 5 inch (127 mm) on each side, of the bifilm/composite membrane laminate are then cut from the roll stock. The EPTFE side of bifilm/composite membrane laminate is treated with a liquid composition of 5% 922 EW hydrolyzed perfluorosulfonic acid polymer (as described in DuPont U.K. patent 1,286,589) in a 5% water/95% ethyl alcohol mixture by pouring the solution onto the square and rubbing it in until the membrane becomes translucent and allowing the laminate to air dry between treatments. The coating cycle is repeated until the membrane retains its clear appearance in the dry state, visually indicating complete filling of the pores of the EPTFE layer with ionomer. A total of 4 coating cycles are required to accomplish this. The bifilm/composite membrane laminate is dried for a period of several days at a temperature of 110° C. to remove residual solvent and to fully consolidate the laminate.

The bifilm composite/membrane laminate is then exposed to a solution of 10% potasium hydroxide, 30% dimethyl sulfoxide and 60% water on a steam bath for 30 minutes to hydrolyze the laminate to the potassium salt form, and washed thoroughly in deionized water.

The hydrolyzed laminate still in the wet condition was tested for tear strength using 3 inch (76 mm) squares. The tear test is Elmendorf Tear, ASTM D1922.

The tear strength is 2 kN/m, about the same strength as unreinforced membrane. Commercial lightly reinforced membrane has a typical wet tear strength of 30 kN/m.

Example 1

Composite Membrane with Unsintered EPTFE

An unsintered expanded PTFE structure (EPTFE), prepared as disclosed in U.S. Pat. Nos. 3,962,153 (Gore) and 3,953,566 (Gore) omitting the sintering step, is used as a reinforcing layer in a composite membrane. The EPTFE has a nominal thickness of 4 mil (0.004 inch, 102 μm) and an apparent density of about 0.38 g/cc with a pore size of 0.2 μm.

Squares, 5 inch (127 mm) on each side, of the EPTFE are soaked with a liquid composition of 5% 922 EW hydrolyzed perfluorosulfonic acid polymer (as described in DuPont U.K. patent 1,286,589) in a 5% water/95% ethyl alcohol mixture, followed by air drying, until the membrane becomes translucent visually indicating complete filling or the pores of the EPTFE with ionomer. A total of 4 coating cycles are required to accomplish this. The impregnated EPTFE membrane is air dried and is then exposed to a solution of 10% potassium hydroxide, 30% dimethyl sulfoxide and 60% water on a steam bath for 30 minutes to hydrolyze the membrane to the potassium salt form, and washed thoroughly in deionized water.

The hydrolyzed membrane still in the wet condition was tested for using tear strength ASTM D1922 using 3 inch (76 mm) squares The tear strength was 160 kN/m.

Composite membranes made with unsintered EPTFE have a much superior tear strength to composite membranes made with sintered EPTFE.

Example 2

Composite Membrane for Chloralkali Electrolysis

An unsintered expanded microporous PTFE support (EPTFE), prepared as disclosed in U.S. Pat. Nos. 3,962,153 (Gore) and 3,953,566 (Gore) omitting the sintering step, is used as a microporous support in a composite membrane. The EPTFE has a nominal thickness of 4 mil (100 μm) and an apparent density of about 0.38 g/cc with a pore size of 0.2 μm.

A bifilm of 1 mil (25 μm) 1050 EW highly fluorinated carboxylate film adhered to 4 mil (0.004 inch, 100 μm) 1080 EW sulfonyl fluoride film is prepared by coextrusion of the component polymers to make a two layer film. The bifilm is then laminated to the microporous EPTFE support by vacuum lamination at 280° C. with the sulfonyl fluoride side of the bifilm contacting the support.

Squares, 5 inch (127 mm) on each side, of the bifilm laminate are then cut from the roll stock. The bifilm laminate is exposed to a solution of 10 weight % potasium hydroxide, 30 weight % dimethyl sulfoxide and 60 weight % water on a steam bath for 30 minutes to hydrolyze the laminate to the potassium salt form, and washed thoroughly in deionized water.

The EPTFE support side of the laminate is then sprayed several times with a liquid composition of 5 weight % perfluorosulfonic acid polymer (copolymer of TFE and PDMOF) having an equivalent weight of 922 (12 IXR) in a 5 weight % water/95 weight % ethyl alcohol mixture, followed by drying, until the membrane becomes translucent and allowing the laminate to air dry between treatments. The coating cycle is repeated until the membrane retains its clear appearance in the dry state, visually indicating complete filling of the pores of the EPTFE layer with ionomer. A total of 4 coating cycles are required to accomplish this. The bifilm laminate is dried for a period of several days at a temperature of 110° C. to remove residual solvent and to fully consolidate the laminate and form a composite membrane suitable for testing electrical performance.

The membrane is then coated on both sides with gas release coating according to the teachings of U.S. Pat. No. 4,552,631 (Bissot et al.) and put into chloralkali cells for testing.

After 94 days continuous cell testing duplicate membranes show 3.04V, 95.3% current efficiency and 3.07V, 96.4% current efficiency. This performance is equivalent to that of good commercial membranes.

Claims (31)

What is claimed is:
1. A composite membrane comprising an ion exchange polymer and a support of expanded polytetrafluoroethylene polymer having a porous microstructure of polymeric fibrils, said expanded polytetrafluoroethylene polymer being at least about 85% crystalline.
2. The composite membrane of claim 1 wherein said expanded polytetrafluoroethylene polymer is at least about 90% crystalline.
3. The composite membrane of claim 1 wherein said expanded polytetrafluoroethylene polymer is at least about 95% crystalline.
4. The composite membrane of claim 1 wherein said expanded polytetrafluoroethylene polymer is at least about 98% crystalline.
5. The composite membrane of claim 1 wherein said expanded polytetrafluoroethylene polymer has a microstructure of nodes interconnected by fibrils.
6. The composite membrane of claim 1 where the ion exchange polymer is highly fluorinated.
7. The composite membrane of claim 6 wherein said membrane has a wet tear strength as determined by ASTM D1922 of at least about 10 kN/m.
8. The composite membrane of claim 6 wherein said membrane has a wet tear strength as determined by ASTM D1922 of at least about 100 kN/m.
9. The composite membrane of claim 6 wherein said membrane has a wet tear strength as determined by ASTM D1922 of at least about 200 kN/m.
10. The composite membrane of claim 6 wherein said ion exchange polymer has an ion exchange ratio of about 8 to about 23.
11. The composite membrane of claim 6 wherein said ion exchange polymer has an ion exchange ratio of about 9 to about 14.
12. The composite membrane of claim 6 wherein said ion exchange polymer has an ion exchange ratio of about 10 to about 13.
13. The composite membrane of claim 6 wherein said ion exchange polymer has sulfonate ion exchange groups.
14. The composite membranes of claim 13 wherein said ion exchange polymer is perfluorinated.
15. The composite membrane of claim 14 further comprising a layer of highly fluorinated carboxylate polymer.
16. The composite membrane of claim 14 further comprising an unreinforced layer of sulfonate polymer adjacent to said porous support and a layer of highly fluorinated carboxylate polymer adhered to the side of said sulfonate polymer layer remote from said porous support.
17. The composite membrane of claim 1 having a thickness of 20 μm to about 400 μm.
18. The composite membrane of claim 1 having a thickness of 30 μm to about 60 μm.
19. The composite membrane of claim 1 further comprising a fabric attached to said porous support.
20. The composite membrane of claim 19 wherein the fabric is woven.
21. The composite membrane of claim 19 wherein the fabric is nonwoven.
22. The composite membrane of claim 1 wherein said porous support is fully embedded in said ion exchange polymer.
23. The composite membrane of claim 22 wherein said polymer of porous support comprises less than about 15% by weight of said membrane.
24. The composite membrane of claim 22 wherein a layer of unreinforced ion exchange polymer having a thickness of at least about 2 μm is provided at each surface of said membrane.
25. The composite membrane of claim 22 wherein a layer of unreinforced ion exchange polymer having a thickness of at least about 5 μm is provided at each surface of said membrane.
26. The composite membrane of claim 25 wherein said membrane has a wet tear strength as determined by ASTM D1922 of at least about 200 kN/m.
27. The composite membrane of claim 25 wherein said membrane has a wet tear strength as determined by ASTM D1922 of at least about 100 kN/m.
28. A composite membrane comprising a highly fluorinated ion exchange polymer and a porous support consisting essentially of expanded highly fluorinated nonionic polymer having a porous microstructure of polymeric fibrils, said membrane having a wet tear strength as determined by ASTM D1922 of at least about 10 kN/m.
29. An electrochemical cell comprising an anode and a cathode partitioned by a composite membrane comprising an ion exchange polymer and a support of expanded polytetrafluoroethylene polymer having a porous microstructure of polymeric fibrils, said expanded polytetrafluoroethylene polymer being at least about 85% crystalline.
30. A fuel cell comprising an anode and a cathode partitioned by a composite membrane comprising an ion exchange polymer and a support of expanded polytetrafluoroethylene polymer having a porous microstructure of polymeric fibrils said expanded polytetrafluoroethylene polymer being at least about 85% crystalline.
31. An electrochemical cell for producing an alkali metal hydroxide and chlorine by the electrolytic conversion of an alkali metal chloride, said cell comprising an anode and a cathode partitioned by a composite membrane comprising an ion exchange polymer and a support of expanded polytetrafluoroethylene polymer having a porous microstructure of polymeric fibrils, said expanded polytetrafluoroethylene polymer being at least about 85% crystalline.
US09070040 1997-05-02 1998-04-30 Composite membrane with highly crystalline porous support Active US6110333A (en)

Priority Applications (2)

Application Number Priority Date Filing Date Title
US4681497 true 1997-05-02 1997-05-02
US09070040 US6110333A (en) 1997-05-02 1998-04-30 Composite membrane with highly crystalline porous support

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
US09070040 US6110333A (en) 1997-05-02 1998-04-30 Composite membrane with highly crystalline porous support

Publications (1)

Publication Number Publication Date
US6110333A true US6110333A (en) 2000-08-29

Family

ID=21945535

Family Applications (1)

Application Number Title Priority Date Filing Date
US09070040 Active US6110333A (en) 1997-05-02 1998-04-30 Composite membrane with highly crystalline porous support

Country Status (2)

Country Link
US (1) US6110333A (en)
WO (1) WO1998050457A1 (en)

Cited By (57)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US20020144944A1 (en) * 2001-02-26 2002-10-10 Ausimont S.P.A. Porous hydrophilic membranes
US20020185423A1 (en) * 2000-12-12 2002-12-12 Boyd Brian T. Device and method for generating and applying ozonated water
US6531238B1 (en) 2000-09-26 2003-03-11 Reliant Energy Power Systems, Inc. Mass transport for ternary reaction optimization in a proton exchange membrane fuel cell assembly and stack assembly
US20030059666A1 (en) * 2001-09-21 2003-03-27 Kostantinos Kourtakis Anode electrocatalysts for coated substrates used in fuel cells
WO2003105253A2 (en) * 2002-06-10 2003-12-18 E.I. Du Pont De Nemours And Company Carboxylic acid-based ionomer fuel cells
EP1378952A1 (en) * 2002-04-22 2004-01-07 E.I. Du Pont De Nemours And Company Treated gas diffusion backings and their use in fuel cells
US20040018410A1 (en) * 2002-06-10 2004-01-29 Hongli Dai Additive for direct methanol fuel cells
US6689501B2 (en) 2001-05-25 2004-02-10 Ballard Power Systems Inc. Composite ion exchange membrane for use in a fuel cell
WO2004025800A2 (en) * 2002-09-13 2004-03-25 E.I. Du Pont De Nemours And Company Membranes for fuel cells
US20050043487A1 (en) * 2003-08-19 2005-02-24 Felix Vinci Martinez Membranes of fluorinated ionomer blended with nonionomeric fluoropolymers for electrochemical cells
WO2005098100A1 (en) * 2004-04-01 2005-10-20 E. I. Du Pont De Nemours And Company Rotary process for forming uniform material
US20050255370A1 (en) * 2002-07-01 2005-11-17 Figueroa Juan C Vapor deposited catalysts and their use in fuel cells
US20050255372A1 (en) * 2002-01-22 2005-11-17 Lertola James G Unitized membrane electrode assembly and process for its preparation
US20050260464A1 (en) * 2004-01-20 2005-11-24 Raiford Kimberly G Processes for preparing stable proton exchange membranes and catalyst for use therein
WO2006008615A1 (en) * 2004-07-13 2006-01-26 Toyota Jidosha Kabushiki Kaisha Production method for fuel cell
US20060073966A1 (en) * 2003-02-13 2006-04-06 Kostantinos Kourtakis Electrocatalysts and processes for producing
US20060145782A1 (en) * 2005-01-04 2006-07-06 Kai Liu Multiplexers employing bandpass-filter architectures
US20060150398A1 (en) * 2003-07-22 2006-07-13 Brunk Donald H Process for making planar framed membrane electrode assembly arrays, and fuel cells containing the same
US20060204654A1 (en) * 2005-03-11 2006-09-14 Bha Technologies, Inc. Method of making a composite membrane
US20060201874A1 (en) * 2005-03-11 2006-09-14 Bha Technologies, Inc. Composite membrane
WO2006102490A2 (en) 2005-03-24 2006-09-28 E.I. Dupont De Nemours And Company Continuous coating process for composite membranes
US20060286435A1 (en) * 2004-05-27 2006-12-21 Kostantinos Kourtakis Fuel cells and their components using catalysts having a high metal to support ratio
US20070038240A1 (en) * 2002-07-22 2007-02-15 Florencia Lim Catheter balloon having impregnated balloon skirt sections
US20070111084A1 (en) * 2004-10-05 2007-05-17 Law Clarence G Methanol tolerant catalyst material containing membrane electrode assemblies and fuel cells prepared therewith
US20070202764A1 (en) * 2005-04-01 2007-08-30 Marin Robert A Rotary process for forming uniform material
WO2007108950A2 (en) 2006-03-13 2007-09-27 E. I. Du Pont De Nemours And Company Pem having improved inertness against peroxide radicals and corresponding membrane electrode assemblies
US7306841B2 (en) 1999-08-12 2007-12-11 Bridger Biomed, Inc. PTFE material with aggregations of nodes
US20080026275A1 (en) * 2004-05-27 2008-01-31 Kostantinos Kourtakis Sol-Gel Derived Composites Comprising Oxide or Oxyhydroxide Matrices With Noble Metal Components and Carbon for Fuel Cell Catalysts
US20080105629A1 (en) * 2006-11-08 2008-05-08 Donaldson Company, Inc. Systems, articles, and methods for removing water from hydrocarbon fluids
US20080161612A1 (en) * 2006-12-21 2008-07-03 Zhen-Yu Yang Partially fluorinated ionic compounds
US20080160351A1 (en) * 2006-12-20 2008-07-03 Vinci Martinez Felix Process for producing dispersions of highly fluorinated polymers
US20080161429A1 (en) * 2006-12-20 2008-07-03 Vinci Martinez Felix Process for producing re-dispersable particles of highly fluorinated polymer
US20080177088A1 (en) * 2006-10-04 2008-07-24 Teasley Mark F Arylene fluorinated sulfonimide compositions
US20080214732A1 (en) * 2006-10-04 2008-09-04 Teasley Mark F Process for the preparation of arylene fluorinated sulfonimide polymers and membranes
US20080217182A1 (en) * 2007-03-08 2008-09-11 E. I. Dupont De Nemours And Company Electroplating process
CN100425332C (en) 2006-12-07 2008-10-15 浙江理工大学 Preparation method of membrane-covered filter material for high-temperature flue gas/dust integrated treatment
US20090061205A1 (en) * 2007-09-04 2009-03-05 Fujifilm Corporation Crystalline polymer microporous film, manufacturing method of the same, and filtration filter
US20090136817A1 (en) * 2006-10-04 2009-05-28 Teasley Mark F Arylene fluorinated sulfonimide polymers and membranes
US20090159526A1 (en) * 2006-05-19 2009-06-25 Fujifilm Corporation Crystalline polymer microporous membrane, method for producing same, and filter for filtration
US20090176141A1 (en) * 2007-09-04 2009-07-09 Chemsultants International, Inc. Multilayered composite proton exchange membrane and a process for manufacturing the same
US20090182066A1 (en) * 2007-12-27 2009-07-16 E. I. Du Pont De Nemours And Company Crosslinkable fluoropolymer, crosslinked fluoropolymers and crosslinked fluoropolymer membranes
US20100051535A1 (en) * 2008-09-02 2010-03-04 Fujifilm Corporation Crystalline polymer microporous membrane, method for producing the same, and filter for filtration
US20100093878A1 (en) * 2007-12-27 2010-04-15 E.I. Du Pont De Nemours And Company Crosslinkable fluoropolymer, crosslinked fluoropolymers and crosslinked fluoropolymer membranes
WO2010075492A1 (en) 2008-12-23 2010-07-01 E. I. Du Pont De Nemours And Company Process to produce catalyst coated membranes for fuel cell applications
US20100292351A1 (en) * 2007-12-20 2010-11-18 E.I Du Pont De Nemours And Company Process to prepare crosslinkable trifluorostyrene polymers and membranes
US7838594B2 (en) 2006-10-04 2010-11-23 E.I. Du Pont De Nemours And Company Bridged arylene fluorinated sulfonimide compositions and polymers
US20100323277A1 (en) * 2003-03-27 2010-12-23 Robert Roberts Isotropic nano crystallites of polytetrafluoroethylene (ptfe) resin and products thereof that are biaxially planar oriented and form stable
US20110046247A1 (en) * 2007-12-20 2011-02-24 E.I. Du Pont De Nemours And Company Crosslinkable monomer
US20110091790A1 (en) * 2008-03-07 2011-04-21 Johnson Matthey Public Limited Company Ion-conducting membrane structures
US20110218256A1 (en) * 2006-12-21 2011-09-08 Zhen-Yu Yang Partially fluorinated cyclic ionic polymers and membranes
US20110230575A1 (en) * 2007-12-20 2011-09-22 E.I. Du Pont De Nemours And Company Crosslinkable trifluorostyrene polymers and membranes
US8058383B2 (en) 2006-12-18 2011-11-15 E. I. Du Pont De Nemours And Company Arylene-fluorinated-sulfonimide ionomers and membranes for fuel cells
WO2012024484A1 (en) 2010-08-18 2012-02-23 E. I. Du Pont De Nemours And Company Durable ionomeric polymer for proton exchange membrane and membrane electrode assemblies for electrochemical fuel cell applications
US20120115066A1 (en) * 2004-11-01 2012-05-10 GM Global Technology Operations LLC Method for stabilizing polyelectrolyte membrane films used in fuel cells
DE112010005034T5 (en) 2009-12-29 2013-01-03 E.I. Du Pont De Nemours And Company Polyarylene ionomers
DE112010005036T5 (en) 2009-12-29 2013-04-11 E.I. Du Pont De Nemours And Company Polyarylene ionomer membranes
JP2014067605A (en) * 2012-09-26 2014-04-17 Nitto Denko Corp Polymer electrolytic film and fuel battery using the same

Families Citing this family (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP5209165B2 (en) * 2000-03-22 2013-06-12 ビクトレックス マニュファクチャリング リミテッドVictrex Manufacturing Limited Composite ion exchange material
WO2002075835A3 (en) * 2001-03-21 2003-10-16 Mark James Andrews Polymer electrolyte membrane fuel cell
EP1263073A1 (en) * 2001-05-31 2002-12-04 Asahi Glass Co., Ltd. Membrane-electrode assembly for solid polymer electrolyte fuel cells and process for its production
JPWO2005098875A1 (en) * 2004-04-08 2008-03-06 東亞合成株式会社 Preparation and fuel cell electrolyte membrane and membrane electrode assembly
US7309540B2 (en) * 2004-05-21 2007-12-18 Sarnoff Corporation Electrical power source designs and components
CN101416342B (en) * 2006-04-07 2011-10-19 Utc电力公司 Composite water management electrolytes film for fuel battery

Citations (28)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3282875A (en) * 1964-07-22 1966-11-01 Du Pont Fluorocarbon vinyl ether polymers
GB1286589A (en) * 1969-03-27 1972-08-23 Int Nickel Canada Process for the recovery of nickel
US3692569A (en) * 1970-02-12 1972-09-19 Du Pont Surface-activated fluorocarbon objects
US3953566A (en) * 1970-05-21 1976-04-27 W. L. Gore & Associates, Inc. Process for producing porous products
US3962153A (en) * 1970-05-21 1976-06-08 W. L. Gore & Associates, Inc. Very highly stretched polytetrafluoroethylene and process therefor
US4255523A (en) * 1977-06-03 1981-03-10 Asahi Glass Company, Limited Cation exchange membrane of fluorinated polymer for electrolysis and preparation thereof
GB2091166A (en) * 1981-01-16 1982-07-28 Du Pont Membrane, electrochemical cell, and electrolysis process
US4358545A (en) * 1980-06-11 1982-11-09 The Dow Chemical Company Sulfonic acid electrolytic cell having flourinated polymer membrane with hydration product less than 22,000
US4433082A (en) * 1981-05-01 1984-02-21 E. I. Du Pont De Nemours And Company Process for making liquid composition of perfluorinated ion exchange polymer, and product thereof
US4453991A (en) * 1981-05-01 1984-06-12 E. I. Du Pont De Nemours And Company Process for making articles coated with a liquid composition of perfluorinated ion exchange resin
US4552631A (en) * 1983-03-10 1985-11-12 E. I. Du Pont De Nemours And Company Reinforced membrane, electrochemical cell and electrolysis process
US4604170A (en) * 1984-11-30 1986-08-05 Asahi Glass Company Ltd. Multi-layered diaphragm for electrolysis
JPS6266A (en) * 1985-06-19 1987-01-06 Beecham Group Plc Novel compound, its production and pharmaceutical composition
US4849311A (en) * 1986-09-24 1989-07-18 Toa Nenryo Kogyo Kabushiki Kaisha Immobilized electrolyte membrane
US4902308A (en) * 1988-06-15 1990-02-20 Mallouk Robert S Composite membrane
US4940525A (en) * 1987-05-08 1990-07-10 The Dow Chemical Company Low equivalent weight sulfonic fluoropolymers
US4954388A (en) * 1988-11-30 1990-09-04 Mallouk Robert S Fabric reinforced composite membrane
US4997567A (en) * 1984-07-25 1991-03-05 Ben-Gurion University Of The Negev Research And Development Authority Ion-exchange membranes and processes for the preparation thereof
US5082472A (en) * 1990-11-05 1992-01-21 Mallouk Robert S Composite membrane for facilitated transport processes
US5094895A (en) * 1989-04-28 1992-03-10 Branca Phillip A Composite, porous diaphragm
US5183545A (en) * 1989-04-28 1993-02-02 Branca Phillip A Electrolytic cell with composite, porous diaphragm
JPH05171888A (en) * 1991-12-20 1993-07-09 Oriental Kensetsu Kk Construction method of underground structure
US5409785A (en) * 1991-12-25 1995-04-25 Kabushikikaisha Equos Research Fuel cell and electrolyte membrane therefor
US5447636A (en) * 1993-12-14 1995-09-05 E. I. Du Pont De Nemours And Company Method for making reinforced ion exchange membranes
EP0718903A1 (en) * 1994-12-07 1996-06-26 Japan Gore-Tex, Inc. An ion exchange membrane and electrode assembly for an electrochemical cell
US5547551A (en) * 1995-03-15 1996-08-20 W. L. Gore & Associates, Inc. Ultra-thin integral composite membrane
WO1996028242A1 (en) * 1995-03-15 1996-09-19 W.L. Gore & Associates, Inc. Composite membrane
JP5171888B2 (en) 2010-06-09 2013-03-27 日立建機株式会社 Construction machinery

Patent Citations (31)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3282875A (en) * 1964-07-22 1966-11-01 Du Pont Fluorocarbon vinyl ether polymers
GB1286589A (en) * 1969-03-27 1972-08-23 Int Nickel Canada Process for the recovery of nickel
US3692569A (en) * 1970-02-12 1972-09-19 Du Pont Surface-activated fluorocarbon objects
US3953566A (en) * 1970-05-21 1976-04-27 W. L. Gore & Associates, Inc. Process for producing porous products
US3962153A (en) * 1970-05-21 1976-06-08 W. L. Gore & Associates, Inc. Very highly stretched polytetrafluoroethylene and process therefor
US4187390A (en) * 1970-05-21 1980-02-05 W. L. Gore & Associates, Inc. Porous products and process therefor
US4255523A (en) * 1977-06-03 1981-03-10 Asahi Glass Company, Limited Cation exchange membrane of fluorinated polymer for electrolysis and preparation thereof
US4358545A (en) * 1980-06-11 1982-11-09 The Dow Chemical Company Sulfonic acid electrolytic cell having flourinated polymer membrane with hydration product less than 22,000
GB2091166A (en) * 1981-01-16 1982-07-28 Du Pont Membrane, electrochemical cell, and electrolysis process
US4433082A (en) * 1981-05-01 1984-02-21 E. I. Du Pont De Nemours And Company Process for making liquid composition of perfluorinated ion exchange polymer, and product thereof
US4453991A (en) * 1981-05-01 1984-06-12 E. I. Du Pont De Nemours And Company Process for making articles coated with a liquid composition of perfluorinated ion exchange resin
US4552631A (en) * 1983-03-10 1985-11-12 E. I. Du Pont De Nemours And Company Reinforced membrane, electrochemical cell and electrolysis process
US4997567A (en) * 1984-07-25 1991-03-05 Ben-Gurion University Of The Negev Research And Development Authority Ion-exchange membranes and processes for the preparation thereof
US4604170A (en) * 1984-11-30 1986-08-05 Asahi Glass Company Ltd. Multi-layered diaphragm for electrolysis
JPS6266A (en) * 1985-06-19 1987-01-06 Beecham Group Plc Novel compound, its production and pharmaceutical composition
US4849311A (en) * 1986-09-24 1989-07-18 Toa Nenryo Kogyo Kabushiki Kaisha Immobilized electrolyte membrane
US4940525A (en) * 1987-05-08 1990-07-10 The Dow Chemical Company Low equivalent weight sulfonic fluoropolymers
US4902308A (en) * 1988-06-15 1990-02-20 Mallouk Robert S Composite membrane
US4954388A (en) * 1988-11-30 1990-09-04 Mallouk Robert S Fabric reinforced composite membrane
US5094895A (en) * 1989-04-28 1992-03-10 Branca Phillip A Composite, porous diaphragm
US5183545A (en) * 1989-04-28 1993-02-02 Branca Phillip A Electrolytic cell with composite, porous diaphragm
US5082472A (en) * 1990-11-05 1992-01-21 Mallouk Robert S Composite membrane for facilitated transport processes
JPH05171888A (en) * 1991-12-20 1993-07-09 Oriental Kensetsu Kk Construction method of underground structure
US5409785A (en) * 1991-12-25 1995-04-25 Kabushikikaisha Equos Research Fuel cell and electrolyte membrane therefor
US5447636A (en) * 1993-12-14 1995-09-05 E. I. Du Pont De Nemours And Company Method for making reinforced ion exchange membranes
EP0718903A1 (en) * 1994-12-07 1996-06-26 Japan Gore-Tex, Inc. An ion exchange membrane and electrode assembly for an electrochemical cell
US5547551A (en) * 1995-03-15 1996-08-20 W. L. Gore & Associates, Inc. Ultra-thin integral composite membrane
WO1996028242A1 (en) * 1995-03-15 1996-09-19 W.L. Gore & Associates, Inc. Composite membrane
US5599614A (en) * 1995-03-15 1997-02-04 W. L. Gore & Associates, Inc. Integral composite membrane
US5635041A (en) * 1995-03-15 1997-06-03 W. L. Gore & Associates, Inc. Electrode apparatus containing an integral composite membrane
JP5171888B2 (en) 2010-06-09 2013-03-27 日立建機株式会社 Construction machinery

Non-Patent Citations (7)

* Cited by examiner, † Cited by third party
Title
Application No. 08/339,167 filed Nov. 10, 1994 and allowed Nov. 11, 1996, Fuel Cell Incorporating A Reinforced Membrane, Shoibal Banerjee inventor, DuPont Docket No. AD 6227. *
Application No. 08/339,167 filed Nov. 10, 1994 and allowed Nov. 11, 1996, Fuel Cell Incorporating A Reinforced Membrane, Shoibal Banerjee inventor, DuPont Docket No. AD-6227.
Composite Membranes for Fuel Cell Applications, Robert F. Hill and Eric W. Schneider, Jan. 1992, vol. 38, No. 1. *
Composite Membranes for Fuel-Cell Applications, Robert F. Hill and Eric W. Schneider, Jan. 1992, vol. 38, No. 1.
IR Studies on Polytetrafluorethylene, J. Am. Chem. Soc. 81, 1045 1050, (1959), R. E. Moynihan No Month Available. *
IR Studies on Polytetrafluorethylene, J. Am. Chem. Soc. 81, 1045-1050, (1959), R. E. Moynihan No Month Available.
Thermal Characterization of Polymeric Materials, E.A. Turi, ed., Academic Press, New Uork 1981, ch. 1,3 No Month Available. *

Cited By (105)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US7306841B2 (en) 1999-08-12 2007-12-11 Bridger Biomed, Inc. PTFE material with aggregations of nodes
US6531238B1 (en) 2000-09-26 2003-03-11 Reliant Energy Power Systems, Inc. Mass transport for ternary reaction optimization in a proton exchange membrane fuel cell assembly and stack assembly
US6582842B1 (en) 2000-09-26 2003-06-24 Reliant Energy Power Systems, Inc. Enhancement of proton exchange membrane fuel cell system by use of radial placement and integrated structural support system
US6656624B1 (en) 2000-09-26 2003-12-02 Reliant Energy Power Systems, Inc. Polarized gas separator and liquid coalescer for fuel cell stack assemblies
US20020185423A1 (en) * 2000-12-12 2002-12-12 Boyd Brian T. Device and method for generating and applying ozonated water
US6902676B2 (en) * 2001-02-26 2005-06-07 Ausimont S.P.A. Porous hydrophilic membranes
US20020144944A1 (en) * 2001-02-26 2002-10-10 Ausimont S.P.A. Porous hydrophilic membranes
US6689501B2 (en) 2001-05-25 2004-02-10 Ballard Power Systems Inc. Composite ion exchange membrane for use in a fuel cell
US6939640B2 (en) 2001-09-21 2005-09-06 E. I. Dupont De Nemours And Company Anode electrocatalysts for coated substrates used in fuel cells
US20030059666A1 (en) * 2001-09-21 2003-03-27 Kostantinos Kourtakis Anode electrocatalysts for coated substrates used in fuel cells
US20050255372A1 (en) * 2002-01-22 2005-11-17 Lertola James G Unitized membrane electrode assembly and process for its preparation
US7504174B2 (en) * 2002-01-22 2009-03-17 E. I. Du Pont De Nemours & Company Unitized membrane electrode assembly and process for its preparation
EP1378952A1 (en) * 2002-04-22 2004-01-07 E.I. Du Pont De Nemours And Company Treated gas diffusion backings and their use in fuel cells
US20040018410A1 (en) * 2002-06-10 2004-01-29 Hongli Dai Additive for direct methanol fuel cells
WO2003105253A3 (en) * 2002-06-10 2004-12-23 Du Pont Carboxylic acid-based ionomer fuel cells
US20040018411A1 (en) * 2002-06-10 2004-01-29 Hongli Dai Carboxylic acid-based ionomer fuel cells
WO2003105253A2 (en) * 2002-06-10 2003-12-18 E.I. Du Pont De Nemours And Company Carboxylic acid-based ionomer fuel cells
US7402351B2 (en) 2002-06-10 2008-07-22 E.I. Du Pont De Nemours And Company Carboxylic acid-based ionomer fuel cells
US20050255370A1 (en) * 2002-07-01 2005-11-17 Figueroa Juan C Vapor deposited catalysts and their use in fuel cells
US20070038240A1 (en) * 2002-07-22 2007-02-15 Florencia Lim Catheter balloon having impregnated balloon skirt sections
US7981244B2 (en) * 2002-07-22 2011-07-19 Abbott Cardiovascular Systems Inc. Catheter balloon having impregnated balloon skirt sections
WO2004025800A2 (en) * 2002-09-13 2004-03-25 E.I. Du Pont De Nemours And Company Membranes for fuel cells
US20050238938A1 (en) * 2002-09-13 2005-10-27 Rajendran Raj G Membranes for fuel cells
WO2004025800A3 (en) * 2002-09-13 2004-06-17 Du Pont Membranes for fuel cells
US7345005B2 (en) 2003-02-13 2008-03-18 E.I. Du Pont De Nemours And Company Electrocatalysts and processes for producing
US20060073966A1 (en) * 2003-02-13 2006-04-06 Kostantinos Kourtakis Electrocatalysts and processes for producing
US7972988B2 (en) 2003-02-13 2011-07-05 E. I. Du Pont De Nemours And Company Electrocatalysts and processes for producing
US20100092834A1 (en) * 2003-02-13 2010-04-15 Kostantinos Kourtakis Electrocatalysts and processes for producing
US8895139B2 (en) * 2003-03-27 2014-11-25 Robert Roberts Isotropic nano crystallites of polytetrafluoroethylene (PTFE) resin and products thereof that are biaxially planar oriented and form stable
US20100323277A1 (en) * 2003-03-27 2010-12-23 Robert Roberts Isotropic nano crystallites of polytetrafluoroethylene (ptfe) resin and products thereof that are biaxially planar oriented and form stable
US7416804B2 (en) 2003-07-22 2008-08-26 E.I. Du Pont De Nemours And Company Process for making planar framed membrane electrode assembly arrays, and fuel cells containing the same
US20060150398A1 (en) * 2003-07-22 2006-07-13 Brunk Donald H Process for making planar framed membrane electrode assembly arrays, and fuel cells containing the same
US7557164B2 (en) * 2003-08-19 2009-07-07 E. I. Du Pont De Nemours And Company Membranes of fluorinated ionomer blended with nonionomeric fluoropolymers for electrochemical cells
US20050043487A1 (en) * 2003-08-19 2005-02-24 Felix Vinci Martinez Membranes of fluorinated ionomer blended with nonionomeric fluoropolymers for electrochemical cells
US20050260464A1 (en) * 2004-01-20 2005-11-24 Raiford Kimberly G Processes for preparing stable proton exchange membranes and catalyst for use therein
US7582240B2 (en) 2004-04-01 2009-09-01 E. I. Du Pont De Nemours And Company Rotary process for forming uniform material
JP4856625B2 (en) * 2004-04-01 2012-01-18 イー・アイ・デュポン・ドウ・ヌムール・アンド・カンパニーE.I.Du Pont De Nemours And Company Rotation process for forming a uniform material
JP2007531833A (en) * 2004-04-01 2007-11-08 イー・アイ・デュポン・ドウ・ヌムール・アンド・カンパニーE.I.Du Pont De Nemours And Company Rotation process for forming a uniform material
WO2005098100A1 (en) * 2004-04-01 2005-10-20 E. I. Du Pont De Nemours And Company Rotary process for forming uniform material
US20050244639A1 (en) * 2004-04-01 2005-11-03 Marin Robert A Rotary process for forming uniform material
CN1938459B (en) 2004-04-01 2012-03-21 纳幕尔杜邦公司 Rotary process for forming uniform material
US20080026275A1 (en) * 2004-05-27 2008-01-31 Kostantinos Kourtakis Sol-Gel Derived Composites Comprising Oxide or Oxyhydroxide Matrices With Noble Metal Components and Carbon for Fuel Cell Catalysts
US20060286435A1 (en) * 2004-05-27 2006-12-21 Kostantinos Kourtakis Fuel cells and their components using catalysts having a high metal to support ratio
US7727664B2 (en) 2004-07-13 2010-06-01 Toyota Jidosha Kabushiki Kaisha Production method for fuel cell
CN100474678C (en) 2004-07-13 2009-04-01 丰田自动车株式会社 Production method for fuel cell
WO2006008615A1 (en) * 2004-07-13 2006-01-26 Toyota Jidosha Kabushiki Kaisha Production method for fuel cell
US20070111084A1 (en) * 2004-10-05 2007-05-17 Law Clarence G Methanol tolerant catalyst material containing membrane electrode assemblies and fuel cells prepared therewith
US20120115066A1 (en) * 2004-11-01 2012-05-10 GM Global Technology Operations LLC Method for stabilizing polyelectrolyte membrane films used in fuel cells
US8431286B2 (en) * 2004-11-01 2013-04-30 GM Global Technology Operations LLC Method for stabilizing polyelectrolyte membrane films used in fuel cells
US20060145782A1 (en) * 2005-01-04 2006-07-06 Kai Liu Multiplexers employing bandpass-filter architectures
US7588796B2 (en) * 2005-03-11 2009-09-15 Bha Group, Inc. Method of making a composite membrane
US20060204654A1 (en) * 2005-03-11 2006-09-14 Bha Technologies, Inc. Method of making a composite membrane
US20060201874A1 (en) * 2005-03-11 2006-09-14 Bha Technologies, Inc. Composite membrane
US7635062B2 (en) * 2005-03-11 2009-12-22 Bha Group, Inc. Composite membrane
JP4796123B2 (en) * 2005-03-24 2011-10-19 イー・アイ・デュポン・ドウ・ヌムール・アンド・カンパニーE.I.Du Pont De Nemours And Company Continuous coating method for the composite membrane
US20060214325A1 (en) * 2005-03-24 2006-09-28 O'brien William G Continuous coating process for composite membranes
WO2006102490A2 (en) 2005-03-24 2006-09-28 E.I. Dupont De Nemours And Company Continuous coating process for composite membranes
WO2006102490A3 (en) * 2005-03-24 2007-01-18 Du Pont Continuous coating process for composite membranes
US7648660B2 (en) 2005-03-24 2010-01-19 E.I. Du Pont De Nemours And Company Continuous coating process for composite membranes
US20070202764A1 (en) * 2005-04-01 2007-08-30 Marin Robert A Rotary process for forming uniform material
WO2007108950A2 (en) 2006-03-13 2007-09-27 E. I. Du Pont De Nemours And Company Pem having improved inertness against peroxide radicals and corresponding membrane electrode assemblies
US9728800B2 (en) 2006-03-13 2017-08-08 The Chemours Company Fc, Llc Stable proton exchange membranes and membrane electrode assemblies
US8153041B2 (en) 2006-05-19 2012-04-10 Fujifilm Corporation Crystalline polymer microporous membrane, method for producing same, and filter for filtration
US20110049044A1 (en) * 2006-05-19 2011-03-03 Fujifilm Corporation Crystalline polymer microporous membrane, method for producing the same, an dfilter for filtration
US20090159526A1 (en) * 2006-05-19 2009-06-25 Fujifilm Corporation Crystalline polymer microporous membrane, method for producing same, and filter for filtration
US7868086B2 (en) 2006-10-04 2011-01-11 E. I. Du Pont De Nemours And Company Arylene fluorinated sulfonimide polymers and membranes
US20090136817A1 (en) * 2006-10-04 2009-05-28 Teasley Mark F Arylene fluorinated sulfonimide polymers and membranes
US20080214732A1 (en) * 2006-10-04 2008-09-04 Teasley Mark F Process for the preparation of arylene fluorinated sulfonimide polymers and membranes
US20080177088A1 (en) * 2006-10-04 2008-07-24 Teasley Mark F Arylene fluorinated sulfonimide compositions
US7910653B2 (en) 2006-10-04 2011-03-22 E.I. Du Pont De Nemours And Company Process for the preparation of arylene fluorinated sulfonimide polymers and membranes
US7838594B2 (en) 2006-10-04 2010-11-23 E.I. Du Pont De Nemours And Company Bridged arylene fluorinated sulfonimide compositions and polymers
US7838612B2 (en) 2006-10-04 2010-11-23 E. I. Du Pont De Nemours And Company Arylene fluorinated sulfonimide compositions
US9795897B2 (en) 2006-11-08 2017-10-24 Donaldson Company, Inc. Systems, articles, and methods for removing water from hydrocarbon fluids
US20080105629A1 (en) * 2006-11-08 2008-05-08 Donaldson Company, Inc. Systems, articles, and methods for removing water from hydrocarbon fluids
CN100425332C (en) 2006-12-07 2008-10-15 浙江理工大学 Preparation method of membrane-covered filter material for high-temperature flue gas/dust integrated treatment
US8058383B2 (en) 2006-12-18 2011-11-15 E. I. Du Pont De Nemours And Company Arylene-fluorinated-sulfonimide ionomers and membranes for fuel cells
US20080161429A1 (en) * 2006-12-20 2008-07-03 Vinci Martinez Felix Process for producing re-dispersable particles of highly fluorinated polymer
US20080160351A1 (en) * 2006-12-20 2008-07-03 Vinci Martinez Felix Process for producing dispersions of highly fluorinated polymers
US7973091B2 (en) 2006-12-20 2011-07-05 E. I. Du Pont De Nemours And Company Process for producing re-dispersable particles of highly fluorinated polymer
US7989513B2 (en) 2006-12-20 2011-08-02 E.I. Du Pont De Nemours And Company Process for producing dispersions of highly fluorinated polymers
US7456314B2 (en) 2006-12-21 2008-11-25 E.I. Du Pont De Nemours And Company Partially fluorinated ionic compounds
US8415070B2 (en) 2006-12-21 2013-04-09 E I Du Pont De Nemours And Company Partially fluorinated cyclic ionic polymers and membranes
US20080161612A1 (en) * 2006-12-21 2008-07-03 Zhen-Yu Yang Partially fluorinated ionic compounds
US20110218256A1 (en) * 2006-12-21 2011-09-08 Zhen-Yu Yang Partially fluorinated cyclic ionic polymers and membranes
US20080217182A1 (en) * 2007-03-08 2008-09-11 E. I. Dupont De Nemours And Company Electroplating process
US8011518B2 (en) * 2007-09-04 2011-09-06 Fujifilm Corporation Crystalline polymer microporous film, manufacturing method of the same, and filtration filter
US20090061205A1 (en) * 2007-09-04 2009-03-05 Fujifilm Corporation Crystalline polymer microporous film, manufacturing method of the same, and filtration filter
US9023553B2 (en) 2007-09-04 2015-05-05 Chemsultants International, Inc. Multilayered composite proton exchange membrane and a process for manufacturing the same
US20090176141A1 (en) * 2007-09-04 2009-07-09 Chemsultants International, Inc. Multilayered composite proton exchange membrane and a process for manufacturing the same
US20110046247A1 (en) * 2007-12-20 2011-02-24 E.I. Du Pont De Nemours And Company Crosslinkable monomer
US8664282B2 (en) 2007-12-20 2014-03-04 E I Du Pont De Nemours And Company Process to prepare crosslinkable trifluorostyrene polymers and membranes
US20110230575A1 (en) * 2007-12-20 2011-09-22 E.I. Du Pont De Nemours And Company Crosslinkable trifluorostyrene polymers and membranes
US20100292351A1 (en) * 2007-12-20 2010-11-18 E.I Du Pont De Nemours And Company Process to prepare crosslinkable trifluorostyrene polymers and membranes
US8071254B2 (en) 2007-12-27 2011-12-06 E. I. Du Pont De Nemours And Company Crosslinkable fluoropolymer, crosslinked fluoropolymers and crosslinked fluoropolymer membranes
US20100093878A1 (en) * 2007-12-27 2010-04-15 E.I. Du Pont De Nemours And Company Crosslinkable fluoropolymer, crosslinked fluoropolymers and crosslinked fluoropolymer membranes
US20090182066A1 (en) * 2007-12-27 2009-07-16 E. I. Du Pont De Nemours And Company Crosslinkable fluoropolymer, crosslinked fluoropolymers and crosslinked fluoropolymer membranes
US20110091790A1 (en) * 2008-03-07 2011-04-21 Johnson Matthey Public Limited Company Ion-conducting membrane structures
US20100051535A1 (en) * 2008-09-02 2010-03-04 Fujifilm Corporation Crystalline polymer microporous membrane, method for producing the same, and filter for filtration
US8151998B2 (en) * 2008-09-02 2012-04-10 Fujifilm Corporation Crystalline polymer microporous membrane, method for producing the same, and filter for filtration
WO2010075492A1 (en) 2008-12-23 2010-07-01 E. I. Du Pont De Nemours And Company Process to produce catalyst coated membranes for fuel cell applications
US20110217621A1 (en) * 2008-12-23 2011-09-08 E. I. Du Pont De Nemours And Company Process to produce catalyst coated membranes for fuel cell applications
DE112010005034T5 (en) 2009-12-29 2013-01-03 E.I. Du Pont De Nemours And Company Polyarylene ionomers
DE112010005036T5 (en) 2009-12-29 2013-04-11 E.I. Du Pont De Nemours And Company Polyarylene ionomer membranes
WO2012024484A1 (en) 2010-08-18 2012-02-23 E. I. Du Pont De Nemours And Company Durable ionomeric polymer for proton exchange membrane and membrane electrode assemblies for electrochemical fuel cell applications
JP2014067605A (en) * 2012-09-26 2014-04-17 Nitto Denko Corp Polymer electrolytic film and fuel battery using the same

Also Published As

Publication number Publication date Type
WO1998050457A1 (en) 1998-11-12 application

Similar Documents

Publication Publication Date Title
US7338692B2 (en) Microporous PVDF films
US5094895A (en) Composite, porous diaphragm
US5183545A (en) Electrolytic cell with composite, porous diaphragm
US6042958A (en) Composite membranes
US3692569A (en) Surface-activated fluorocarbon objects
US5082472A (en) Composite membrane for facilitated transport processes
US4552631A (en) Reinforced membrane, electrochemical cell and electrolysis process
US5834523A (en) Substituted α,β,β-trifluorostyrene-based composite membranes
US6495209B1 (en) Process of making a composite membrane
US4298697A (en) Method of making sheet or shaped cation exchange membrane
US20100167100A1 (en) Composite membrane and method for making
US4272560A (en) Method of depositing cation exchange membrane on a foraminous cathode
EP0661502A2 (en) A heat and moisture exchange device
US4437951A (en) Membrane, electrochemical cell, and electrolysis process
US20060138042A1 (en) Heat-resistant film and composite ion-exchange membrane
US4610762A (en) Method for forming polymer films having bubble release surfaces
US4872958A (en) Ion exchange membrane for electrolysis
US5264100A (en) Fluorine-containing cation exchange membrane for electrolysis having a protruding porous base reinforcing material on one side thereof
US6294612B1 (en) Highly fluorinated ion exchange/nonfunctional polymer blends
US6613215B2 (en) Method for electrolysis of water using a polytetrafluoroethylene supported membrane in electrolysis cells
US20050137351A1 (en) Polymer electrolyte membranes crosslinked by direct fluorination
US6485856B1 (en) Non-woven fiber webs
US4990228A (en) Cation exchange membrane and use
US20060068258A1 (en) Polymer electrolyte membrane, membrane-electrode assembly for polymer electrolyte fuel cells and process for producing polymer electrolyte membrane
US5981097A (en) Multiple layer membranes for fuel cells employing direct feed fuels

Legal Events

Date Code Title Description
AS Assignment

Owner name: E.I. DU PONT DE NEMOURS AND COMPANY, DELAWARE

Free format text: ASSIGNMENT OF ASSIGNORS INTEREST;ASSIGNOR:KEATING, JAMES THOMAS;REEL/FRAME:009676/0612

Effective date: 19980630

Owner name: DONALDSON COMPANY, INCORPORATED, MINNESOTA

Free format text: ASSIGNMENT OF ASSIGNORS INTEREST;ASSIGNOR:SPETHMANN, JEFFREY E.;REEL/FRAME:009676/0620

Effective date: 19981008

FPAY Fee payment

Year of fee payment: 4

FPAY Fee payment

Year of fee payment: 8

FPAY Fee payment

Year of fee payment: 12

AS Assignment

Owner name: THE CHEMOURS COMPANY FC, LLC, DELAWARE

Free format text: ASSIGNMENT OF ASSIGNORS INTEREST;ASSIGNOR:E. I. DU PONT DE NEMOURS AND COMPANY;REEL/FRAME:035432/0023

Effective date: 20150414

AS Assignment

Owner name: JPMORGAN CHASE BANK, N.A., NEW YORK

Free format text: SECURITY AGREEMENT;ASSIGNORS:THE CHEMOURS COMPANY FC LLC;THE CHEMOURS COMPANY TT, LLC;REEL/FRAME:035839/0675

Effective date: 20150512